Method for manufacturing thermoplastic sheets bearing embossed patterns thereon and an apparatus therefor

ABSTRACT

Provided is a method for manufacturing a thermoplastic resin sheet bearing an embossed pattern, which employs a manufacturing apparatus having a first roll having an elastic material coated surface, a mirror-faced metal, endless belt, which is wound around the first roll and a second roll, and a third roll so provided that the metal, endless belt is wrapped partially around the third roll, which contacts the first roll via the metal, endless belt and which has an embossed pattern formed on one surface. According to this method, the thermoplastic resin sheet, partially melted, is fed between the metal, endless belt, which contacts the first roll, and the third roll. The elastic member is elastically deformed by application of a pressing force between the first and the third roll, while face pressure welding the thermoplastic sheet by using the first and the third rolls to transfer the embossed pattern and to cool the thermoplastic resin sheet. A surface temperature for the third roll of from 0° C. to (resin&#39;s Tg +20)°C. is maintained when the thermoplastic resin sheet is formed of an amorphous resin, and a surface temperature for the third roll of 0° C. to (resin&#39;s m.p. −30)°C. is maintained when the thermoplastic resin sheet is formed of a crystalline resin. Subsequently, face pressure welding of the thermoplastic resin sheet is performed by using the metal, endless belt relative to the third roll.

This application is a reissue application of U.S. Ser. No. 08/811,567,filed Mar. 5, 1997, now U.S. Pat. No. 5,958,309, issued on Sep. 28,1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for manufacturingthermo-plastic sheets having an embossed pattern, and an apparatustherefor, to be used for manufacturing sheets having a reflectivecapability.

2. Description of Related Art

Recently, thermoplastic sheets having a reflective capability (plasticreflection panels), which are produced by performing a microprismprocess on the surface of thermo-plastic sheets, have been employed inthe reflection panel field, the fashion field, and the architecturalfield.

In the United States, reflective sheets of the glass bead type and cubecorner types have been approved as sheets having a reflectivecapability. In general, the glass bead reflective sheets are superiorfor short-distance visibility, and the cube corner reflective sheets aresuperior for long-distance visibility and luminance because of theirreflective capability.

When manufacturing a reflective sheet of the cube corner type, anembossed pattern on an embossed pattern forming die must be transferredexactly to a thermo-plastic sheet.

It is especially important when processing a thermo-plastic sheet thatit be pressed against an embossed pattern die at an adequate temperatureand by the application of an adequate pressure, and that the applicationof the pressure be continued for a predetermined period of time.

A continuous pressing method (see Japanese Examined Patent PublicationNo. Sho 60-56103) and a belt method (see Japanese Examined PatentPublication No. Sho 5-17023) for manufacturing reflective sheets havebeen proposed as conventional methods that satisfy the aboverequirements.

With the continuous pressing method, an overlapping solid-state sheetmaterial is continuously fed to a belt, and a plurality of pressingmeans having heating and cooling functions press embossed pattern moldsagainst the sheet material to transfer patterns to the sheet material.

With the belt method, a belt bearing an embossed pattern mold and athermoplastic sheet are gripped by a pair of rollers and pressedtogether to transfer the pattern to the sheet.

The production speed attained by the continuous pressing method,however, is slow, and the apparatus that is used is large andcomplicated.

Since for the belt method, the belt itself carries the embossed pattern,a problem arises concerning the durability of the belt that serves asthe mold.

Although not presently being used for the manufacture of reflectivesheets, the sheet manufacturing techniques described in JapaneseUnexamined Patent Publication No. Hei 6-55613, Japanese UnexaminedUtility Model Publication No. Hei 3-6919, and Japanese UnexaminedUtility Model Publication No. Hei 1-83092 could be applied for the beltmethod for the manufacture of reflective sheets from a sheet resin thatis melted and extruded through a die by an extruder.

However, were the technique described in Japanese Unexamined PatentPublication No. Hei 6-55613 used, the sheet would be insufficientlytransparent when a nucleus-generating agent did not contain anyadditives. Also, were the technique in Japanese Utility ModelPublication No. Hei 3-6919 used, if the molding speed was increased, thesurface glossiness on the belt side would be degraded because the facepressing interval would be too short. Any technique in JapaneseUnexamined Utility Model Publication No. Hei 1-83092 was used, eventhough an elastic member was employed, as this would be a belt that wascoated with rubber, a problem would arise concerning its durability.

SUMMARY OF THE INVENTION

It is therefore one object of the present invention to provide a methodby which thermo-plastic resin sheets, bearing a highly transparentembossed pattern, can be manufactured with high reproducibility, and anapparatus therefor.

According to the present invention, a method for manufacturing athermo-plastic resin sheet bearing an embossed pattern, which employs amanufacturing apparatus, includes a first roll having an elasticmaterial coated surface, a mirror-faced metal, endless belt, which iswound around the first roll and a second roll, and a third roll soprovided that the metal, endless belt is wrapped partially around thethird roll, which contacts the first roll via the metal, endless beltand which has an embossed pattern formed on one surface, comprises thesteps of:

feeding the thermo-plastic resin sheet, partially melted, between themetal, endless belt, which contacts the first roll, and the third roll;

elastically deforming the elastic member by application of a pressingforce between the first and the third roll, while face pressure weldingthe thermo-plastic sheet by using the first and the third rolls totransfer the embossed pattern and to cool the thermo-plastic resinsheet;

maintaining a surface temperature for the third roll of from 0° C. to(resin's Tg +20)°C. when the thermo-plastic resin sheet is formed of anamorphous resin;

maintaining a surface temperature for the third roll of 0° C. to(resin's m.p. −30)°C. when the thermo-plastic resin sheet is formed of acrystalline resin; and

performing face pressure welding of the thermo-plastic resin sheet byusing the metal, endless belt relative to the third roll.

The partially melted thermo-plastic resin sheet is one that is obtainedimmediately after the resin is melted and is extruded through the die ofan extruder, or one that is obtained by heating a solid-statethermo-plastic resin sheet.

The thermo-plastic resin sheet of the present invention includesthermo-plastic resin sheets having relatively different thicknesses.

The thermo-plastic resin sheet may consist of a single layer or ofmultiple layers of thermo-plastic resin sheets.

The amorphous resin includes an acrylic resin, polycarbonate andpoly(vinyl chloride). This resin may include a nucleus-generating agent,such as sorbitol, benzoic aluminum, polypropylene or sodium.

When the thermo-plastic resin sheet is formed of the amorphous resin andwhen the surface temperature of the third roll is higher than (resin'sTg +20)°C., mold breaking tends to occur when the sheet is peeled fromthe third roll. Preferably, the surface temperature is (resin's Tg)°C.or lower, and more preferably, (resin's Tg −10)°C. or lower.

The crystalline resin includes polypropylene.

When the thermo-plastic resin sheet is formed of the crystalline resin,and when the surface temperature of the third roll is higher than(resin's m.p. −30)°C., mold breaking tends to occur when the sheet ispeeled from the third roll. Preferably, the surface temperature is(resin's m.p. −50)°C., and more preferably, (resin's m.p. −70)°C. orlower.

Temperature adjustment means employing water cooling, etc., can beprovided for the third roll to hold its temperature within the abovedescribed temperature range.

Preferably, the temperature of the belt is maintained so that it is thesame as that of the third roll.

According to the present invention, the surface roughness of the mirrorfinish of the metal, endless belt is, for example, 3 S or lower,preferably, 1 S or lower, and even more preferably 0.5 S or lower. Whenthe surface roughness is greater than 3 S, it is difficult to obtain anappropriately smooth face for the thermo-plastic resin sheet.

The material used for the endless belt can be stainless steel, carbonsteel, or a titanium alloy.

Although the endless belt has an arbitrary thickness, it is preferably0.3 to 1.5 mm. When the belt is thinner than 0.3 mm, the strength of thebelt is reduced and deterioration of its durability occurs. When thebelt is thicker than 1.5 mm, the diameter of a roll around which thebelt is installed must be increased, and the apparatus will thereforebecome larger. In addition, heating and cooling efficiency are degraded,and manufacturing costs are increased.

Although the kind of elastic material that is used is determinedarbitrarily, a fluorocarbon rubber, silicone rubber, EPT, or EPDM can beused. The metal that is used for the elastic member may contain powderedsilver or copper to provide increased thermal conductivity.

The thickness of the elastic member is preferably 1 mm or greater, andmore preferably 3 mm or greater. When the elastic member is thinner than1 mm, the elasticity effect is reduced, and the face welding pressureinterval relative to the thermo-plastic resin sheet is reduced. Inaddition, cushioning is reduced, and a resin bank tends to occur in theportion of the thermo-plastic resin sheet fed between the endless beltand the third roll. The upper limit of the thickness is about 50 mm.When the thickness is greater than this, a problem with its durabilityor with its thermal conductivity tends to arise.

The embossed pattern is arbitrarily selected, but when the sheet is usedas a sheet having a reflective capability, the embossed pattern is atriangular pyramidal diamond cut pattern (cube corner pattern). The sizeof the elements in a continuous arrangement that is employed to form thepattern is determined arbitrarily, and an element need only have asimilar figure.

The first and the second rolls suffice for the rolls around which themetal, endless belt is installed. One more roll may be provided for themetal, endless belt to cool or to heat it on its way to the first roll.

According to the present invention, when a thermo-plastic resin sheet isto be fed between a metal, endless belt, which contacts the first roll,and the third roll, the thermo-plastic resin sheet contacts the endlessbelt and the roll at the same time. Thus, the transfer of the embossedpattern to the partially melted resin that has a low viscosity by thethird roll can be accompanied by the elastic deformation of the elasticmember. Then, since face pressure welding and cooling are performed bythe third roll, the breaking of a mold, which occurs when the embossedpattern is peeled from the mold can be prevented. As a result,reproducibility for the embossed pattern can be increased.

When the thermo-plastic resin sheet is brought into contact with themetal, endless belt or the roll, the melting resin is cooled andsolidified before the embossed pattern is transferred to it.

According to the present invention, it is preferable that the pressureduring the face pressure welding of the thermo-plastic resin sheet,which accompanies the elastic deformation of the elastic member, be 0.1MPa to 20.0 MPa, and that the pressure during the face pressure weldingof the thermoplastic resin sheet, which accompanies no elasticdeformation of the elastic member, be 0.1 MPa to 0.5 MPa.

When the face pressure is equal to or lower than 0.1 MPa, transfer andcooling efficiency are deteriorated. Especially when the embossedpattern is transferred to the thermo-plastic resin sheet, and when theprocessing speed is increased by employing a low face pressure, patternblurring (the returning to the mold of the embossed pattern that hasbeen transferred) tends to occur.

If the face pressure is higher than 20.0 MPa or 0.5 MPa, the belttension is increased, and this is not preferable for its service life.

According to the present invention, an apparatus, for manufacturing athermo-plastic resin sheet bearing an embossed pattern, comprises:

a first roll, which has an elastic material coated surface;

a metal, endless belt, which has a mirror-faced surface; and

a third roll, the face of which is an embossed pattern, the third rollbeing so provided as to contact the first roll via the metal, endlessbelt and further to wrap the metal, endless belt around the third roll.

In short, this is an apparatus for carrying out the above describedmanufacturing method.

Another roll may be provided along the endless belt to increase thecooling efficiency for the metal, endless belt that moves toward thefirst roll.

In this invention, preferably the hardness (conforming to JIS K6301 A)of the elastic material is 95 degrees or less.

When the hardness is greater than 95 degrees, the elastic property isreduced, and a resin bank tends to appear when a partially meltedthermo-plastic resin sheet is brought into contact with the third rolland the metal, endless belt at the same time to perform face pressurewelding. The hardness of the elastic material is preferably 60 degreesor less.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram, according to a first embodiment of thepresent invention, of an apparatus that is used for a method formanufacturing thermo-plastic resin sheets having an embossed pattern;

FIG. 2 is an enlarged diagram showing an embossed pattern formation rollaccording to the first embodiment of the present invention;

FIG. 3 is a cross-sectional view taken along line A—A in FIG. 2;

FIG. 4 is an enlarged diagram illustrating the thermo-plastic resinsheet having an embossed pattern according to the present invention;

FIG. 5 is a cross-sectional view of line B—B in FIG. 4; and

FIG. 6 is a schematic diagram according to the second embodiment of thepresent invention illustrating an apparatus that is used for a methodfor manufacturing the thermo-plastic resin sheet having an embossedpattern.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

First Embodiment

A method and an apparatus according to a first embodiment of the presentinvention for manufacturing a thermo-plastic resin sheet 11 having anembossed pattern will now be described while referring to FIGS. 1through 5.

The structure of the apparatus in the embodiment for manufacturing thethermo-plastic resin sheet 11 having an embossed pattern will bedescribed.

The apparatus comprises a T die 12 of an extruder, a metal, endless beltthat is wound around a first roll 13 and a second roll 14; a third roll33, for an embossed pattern formation, that contacts the first roll 13via the metal, endless belt 15; and a fourth roll 17, provided in thevicinity of the second roll 14, and two pressing rolls (back rolls) 34for pressing the thermo-plastic resin sheet 11.

The first roll 13 is coated with an elastic material 18, such as asilicone rubber. The elastic material 18 has a hardness (conforming toJIS K6301A) of 95 degrees or less, and a thickness of 1 mm to 50 mm.

The metal, endless belt 15 is formed of stainless steel, and has amirror finish face whose surface roughness is equal to or less than 0.5S.

At least one of the rotary shafts 19 of the first and the second rolls13 and 14 is coupled to rotating driving means (not shown).

As is shown in FIGS. 2 and 3, a mold 35 is formed on the outer,peripheral surface of the third roll 33 to transfer an embossed pattern36 (see FIGS. 4 and 5) to the thermo-plastic resin sheet 11. The mold 35has a raised and recessed profile that corresponds to a triangularpyramid diamond cut pattern for a sheet having a reflective capability.

The third roll 33 is located at the position where the endless belt 15extending between the first and the second rolls 13 and 14 is recessedinward, as if one part of the outer periphery of the third roll 33 werewrapped in the endless belt 15. More specifically, during themanufacturing process for the thermo-plastic resin sheet 11 having anembossed pattern, the endless belt 15 and the sheet 11 drifts whilebeing wrapped around one part of the outer periphery of the third roll33. The two pressing rolls 34 are so located that they press thethermo-plastic resin sheet 11 against the embossed pattern formationroll 33 from the rear face of the endless belt 15.

The fourth roll 17 is used to guide the thermo-plastic resin sheet, sothat the endless belt 15 performs face pressure welding of the sheet 11at one part of the outer periphery of the second roll 14.

A water cooled temperature adjustment means (not shown) for regulatingthe surface temperatures is provided for the rolls 13, 14, 32 and 33.

As is indicated by a chain line in FIG. 1, another roll 32 may beprovided before the first roll 13 along the metal, endless belt 15 inorder to increase the cooling efficiency of the endless belt 15 thatgoes to the first roll 13.

An explanation will now be given for the method employed in thisembodiment, which uses the above described apparatus, to manufacture athermo-plastic resin sheet 11 having an embossed pattern in thisembodiment.

First, the temperature of the third roll 33 is controlled to maintain asurface temperature of 0° C. to (resin's Tg +20)°C. when thethermoplastic resin sheet 11 is formed of an amorphous resin, and asurface temperature of 0° C. to (resin's m.p −30)°C. when thethermoplastic resin sheet 11 is formed of crystalline resin.

After the thermo-plastic resin sheet 11 is melted and extruded by the Tdie 12 of the extruder, the sheet 11 is fed between the first roll 13and the embossed pattern formation roll 33, the sheet 11 contacting theendless belt 15, which is in contact with the first roll 13, and thethird roll 33 at substantially the same time. The sheet 11 is thenwelded under pressure applied by the rolls 13 and 33 and cooled. At thistime, the elastic material 18 is compressed and elastically deformed bya pressing force exerted between the first roll 13 and the third roll 33and is elastically deformed. In the surface area described by angles θ₁originating at the centers of the rolls 13 and 33, where the elasticmaterial 18 is elastically deformed, face pressure welding is performedon the sheet 11 by the rolls 13 and 33, and the embossed pattern of themold 35 on the roll 33 is transferred to the sheet 11. The face pressureapplied to the sheet 11 is 0.1 MPa to 20.0 MPa.

Sequentially, the thermo-plastic resin sheet 11 is pressed against thethird roll 33 by the endless belt 15 and cooled. The sheet 11, which ispressed against the roll 33 by the pressing rolls 34 via the endlessbelt 15, is wrapped around the roll 33 the distance described by anangle θ₂ originating at the center of the roll 33, and face pressurewelding of the sheet 11 is performed by the endless belt 15 and the roll33 or in the surface area described by the angle θ₂, while the facepressure relative to the sheet 11 at this time is 0.01 MPa to 0.5 MPa.

Then, the thermo-plastic resin sheet 11 is moved to the second roll 14by the travel of the endless belt 15. The sheet 11 on which the embossedpattern is formed is pressed against the second roll 14 under pressureapplied via the endless belt 15, and cooled. Within the surface areadescribed by an angle θ₃ originating at the center of the roll 14, facepressure welding of the sheet 11, which is guided by the second roll 17and is wrapped around the second roll 14, is performed. The facepressure at this time is 0.01 MPa to 0.5 MPa.

According to this embodiment, within the surface areas of the first roll13 and the embossed pattern formation roll 33 that are described by theangles θ₁, while the elastic material 18 is elastically deformed, facepressure welding and cooling of the sheet 11 are performed by the rolls13 and 33, via the endless belt 15, to transfer the embossed pattern 36to the sheet 11. Thus, the embossed pattern 36 can be formed at a highspeed on the thermo-plastic resin sheet 11 that has been melted andextruded. The resultant sheet 11 bearing the embossed pattern 36 hassatisfactory transparency.

Following the face pressure welding and the cooling, within the surfacearea described by the angle θ₂ of the embossed pattern formation roll33, face pressure welding and cooling are performed on the sheet 11 bythe endless belt 15 and the roll 33, and at the surface area of thesecond roll 14 described by the angle θ₃, face pressure welding and thecooling are performed on the sheet 11 by the endless belt 15 and thesecond roll 14. As a result, the transparency of the thermo-plasticresin sheet 11 can be further improved.

Second Embodiment

A method and an apparatus according to a second embodiment of thepresent invention for manufacturing a thermo-plastic resin sheet 11having an embossed pattern will now be described while referring to FIG.6.

The apparatus in the embodiment differs from the apparatus of the firstembodiment in the following ways.

In the apparatus in this embodiment, while the fourth roll 17 of thefirst embodiment is not provided, a first roll 13 coated with an elasticmaterial 18, a second roll 14, a metal, endless belt 15 and a third roll16 are provided in the same manner.

The manufacturing method for the thermo-plastic resin sheet 11, which isemployed by the above apparatus, differs from the method used in thefirst embodiment in that the face pressure welding and cooling are notperformed on a sheet 11 that is guided by a fourth roll 17 while usingthe endless belt 15.

The partially melted thermo-plastic resin sheet 11, which is extruded bya T die 12 in an extruder, is fed between the first and the third rolls13 and 16. Face pressure welding is performed for the sheet 11 by thefirst and the third rolls 13 and 16, and the sheet 11 is then cooled.Following this, face pressure welding of the resultant thermo-plasticresin sheet 11 is performed relative to the third roll 16 along themirror-faced endless belt 15, and the sheet 11 is then cooled.

According to the present invention, at the surface areas described bythe angles θ₁ on the first and the third rolls 13 and 16, while theelastic material 18 is elastically deformed, face pressure welding andcooling are performed on the sheet 11 by the rolls 13 and 16, as it iscarried along the endless belt 15, to transfer an embossed pattern 36 tothe sheet 11. Therefore, the embossed pattern 36 can be transferred at ahigh speed to the thermo-plastic resin sheet 11 that has been melted andextruded. In addition, the resultant sheet 11 bearing the embossedpattern 36 has superior transparency.

In addition to the above face pressure welding and cooling, facepressure welding and cooling are also performed on the sheet 11 by theendless belt 15 and the embossed pattern formation roll 16 at thesurface area of the roll 16 described by the angle θ₂. Thus, thetransparency of the thermo-plastic resin sheet 11 can be furtherenhanced.

Embodiment 1

In Embodiment 1, the conditions for the manufacturing apparatus andmethod were specifically determined as follows.

Diameter of the screw of a single screw extruder: 65 mm

Width of T die: 600 mm

Thermoplastic resin:

poly(vinyl chloride) 50 weight %

(polymerization degree: 1000, Tg: 60° C.)

Resin additive:

plasticizer 45 weight % of DOP(di-2-ethylhexylphthalate)

stabilizer 0.1 weight % of stearic zinc propylene 0.1 weight % ofstearic barium

Thickness of thermoplastic resin sheet: 0.3 mm

Elastic material:

silicone rubber having a thickness of 10 mm and a hardness of 50 degrees

Line speed: 3 m/min

Surface temperature of third roll: 50° C.

Embodiment 2

Only the material for the sheet and the surface temperature of the thirdroll were changed in the method in Embodiment 1.

Thermal plastic resin: polypropylene (m.p.: 160° C.)

Surface temperature of third roll: 70° C.

Embodiment 3

Only the material for the sheet and the surface temperature of the thirdroll were changed in the method in Embodiment 1.

Thermal plastic resin: polycarbonate (Tg: 145° C.)

Surface temperature of third roll: 140° C.

Comparison Example 1

Only the surface temperature of the third roll was changed in the methodin Embodiment 1.

Surface temperature of third roll: 85° C.

Comparison Example 2

Only the surface temperature of the third roll was changed in the methodin Embodiment 1.

Surface temperature of third roll: 140° C.

Comparison Example 3

Only the surface temperature of the third roll was changed in the methodin Embodiment 1.

Surface temperature of third roll: 170° C.

For Embodiments 1 through 3 and Comparison Examples 1 through 3, theobtained thermo-plastic resin sheets were evaluated. The results areshown in Table 1 below.

The evaluation references in Table 1 are as follows.

⊚ . . . sufficient reflective capability

x . . . no reflective capability

TABLE 1 Third roll temperature Sheet resin (° C.) Performance Embodiment1 poly(vinyl chloride) 50 ⊚ Embodiment 2 polypropylene 70 ⊚ Embodiment 3polycarbonate 140 ⊚ Comparison poly(vinyl chloride) 70 x example 1Comparison polypropylene 140 x example 2 Comparison polycarbonate 160 xexample 3

As is apparent from Table 1, the thermo-plastic resin sheets 11 bearingthe embossed pattern in Embodiments 1 through 3 were obtained by theapparatus described in the above embodiments. These sheets 11 weremanufactured with a surface temperature for the third roll 33 of zero to(resin's Tg+20)°C. when the resin for the sheet 11 was an amorphousresin, and with a surface temperature for the third roll 33 of zero to(resin's m.p. −30)°C. when the resin for the sheet 11 was a crystalresin. It is obvious that the embossed pattern of the mold 35 wassatisfactorily transferred to the sheet 11, and that the sheet 11 had asufficient reflective capability.

In Comparison Example 1, although the thermo-plastic resin sheet bearingan embossed pattern was obtained by the apparatus described in theembodiments, the surface temperature of the third roll 33 was higherthan 80° C., which is (resin's Tg +20)°C., so that the mold transfer wasdefective due to the mold breaking when the embossed pattern was peeledfrom the mold, and no reflective capability was confirmed.

In Comparison Example 2, although the thermo-plastic resin sheet bearingan embossed pattern was obtained by the apparatus described in theembodiments, the surface temperature of the third roll 33 was higherthan 130° C., which is (resins' m.p −30)°C., so that the mold transferwas defective due to the mold breaking when the embossed pattern waspeeled from the mold, and no reflective capability was confirmed.

In Comparison Example 3, although the thermo-plastic resin sheet bearingan embossed pattern was obtained by the apparatus described in theembodiments, the surface temperature of the third roll 33 was higherthan 165° C., which is (resins' Tg +20)°C., so that no reflectivecapability was confirmed as in the preceding comparison examples.

What is claimed is:
 1. A method of manufacturing an amorphous thermoplastic resin sheet having an embossed pattern comprising the steps of: providing a manufacturing apparatus comprising a first roll having an outer surface coated with an elastic material, a second roll, a third roll having an embossed pattern provided on an outer surface thereof and a metal endless belt having a mirror-finished surface wound around said first and second rolls and in contact with said third roll; feeding the amorphous thermoplastic resin sheet, in a partially molten state, between the metal endless belt and the third roll; maintaining the outer surface temperature of the third roll of from 0° C. to the amorphous thermoplastic resin's Tg; elastically deforming the elastic material by applying a pressing force between said first and third rolls to conduct face pressure welding of said amorphous thermoplastic resin sheet and cool and transfer the embossed pattern to the amorphous thermoplastic resin sheet; and performing face pressure welding of the amorphous thermoplastic resin sheet having the embossed pattern thereon between the metal endless belt and the third roll.
 2. A method of manufacturing a crystalline thermoplastic resin sheet having an embossed pattern comprising the steps of: providing a manufacturing apparatus comprising a first roll having an outer surface coated with an elastic material, a second roll, a third roll having an embossed pattern provided on an outer surface thereof and a metal endless belt having a mirror-finished surface wound around said first and second rolls and in contact with said third roll; feeding the crystalline thermoplastic resin sheet, in a partially molten state, between the metal endless belt and the third roll; maintaining the outer surface temperature of the third roll of from 0° C. to the crystalline thermoplastic resin's m.p. −30° C.; elastically deforming the elastic material by applying a pressing force of from 0.1-20 MPa between said first and third rolls to conduct face pressure welding of said crystalline thermoplastic resin sheet and cool and transfer the embossed pattern to the crystalline thermoplastic resin sheet; and performing face pressure welding of the crystalline thermoplastic resin sheet having the embossed pattern thereon between the metal endless belt and the third roll at a pressure of from 0.1 0.01-0.5 MPa.
 3. A method for manufacturing a crystalline thermoplastic resin sheet bearing an embossed pattern according to claim 2, wherein, said surface temperature of said third roll is between zero and the resin's m.p. −50° C.
 4. A method for manufacturing an amorphous thermoplastic resin sheet bearing an embossed pattern according to claim 1, wherein the pressure during said face pressure welding of said thermoplastic resin sheet is 0.1 MPa to 20.0 MPa, and wherein said pressure during said face pressure welding of said thermoplastic resin sheet having the embossed pattern thereon is from 0.1 0.01 to 0.5 MPa.
 5. A method for manufacturing an amorphous thermoplastic resin sheet bearing an embossed pattern according to claim 1, wherein the surface roughness of the mirror-finished surface of said metal endless belt is 3 S or lower.
 6. A method for manufacturing a crystalline thermoplastic resin sheet bearing an embossed pattern according to claim 2, wherein the surface roughness of the mirror-finished surface of said metal endless belt is 3 S or lower. 